Generally, a vehicle seat is composed of a seat cushion, a seat back provided to stand on the rear side of the seat cushion, and so on. Furthermore, the seat cushion and the seat back are each composed of a seat cushion frame or seat back frame, a pad material (cushion material), and a trim cover as an upholstery member with which the pad material is covered. For example, according to Japanese Patent Application No. 2011-45622, end treatment for a trim cover is performed as follows: “A J-shaped hook 10 attached to an end of a piece of upholstery 6 is engaged with a J-shaped hook 11 attached to an end of a rear member 7, so that the ends of the piece of upholstery 6 and the rear member are connected and secured” (see Paragraph [0025]).